Abstract: Efficient and stable bifunctional non-noble metal electrocatalytic materials are essential to reduce the cost of hydrogen production by electrolysis. This study constructed iron-doped hierarchical porous amorphous nickel phosphate catalytic materials (Fe-NiOP/NF) on nickel foam (NF) using an electrodeposition combined with chemical etching strategy. This strategy allows the controllable preparation of nanosheets on the conductive substrate nickel foam by electrodeposition and in-situ induction of the nanosheets to a porous structure by chemical etching. The porous structure facilitates mass transfer of electrolyte and gas evolution. Iron doping effectively optimizes the electronic structure of active site Ni by triggering charge redistribution from Ni to Fe. The intrinsic activity normalized by electrochemical active surface area (ECSA) increases by approximately 2.95 times compared to the undoped sample. The Fe-NiOP/NF catalytic material exhibits excellent bifunctional catalytic activity in both the hydrogen evolution reaction and the oxygen evolution reaction, with a hydrogen evolution overpotential of 246 mV and an oxygen evolution overpotential of 291 mV at a current density of 500 mA·cm^-2. When used as a bifunctional catalytic material in anion exchange membrane watersis (AEMWE) devices, Fe-NiOP/NF achieves catalytic performances of 1.92 V@1 A·cm^-2 and 2.13 V@2 A·cm^-2 at 70 ℃, and operates steadily for longer than 200 h at a current density of 1 A·cm^-2. The electrocatalytic material Fe-NiOP/NF developed in this study possesses the advantages of simple synthesis method, high performance, and high stability, providing a new method for development of the electrode for industrial-level green hydrogen production.

Key words: hydrogen energy, porous structure, amorphous material, large current density, anion exchange membrane water electrolysis